Just when you thought our trigger-happy leaders might finally have run out of easy targets – disabled people who can't run from the Atos testers, foster parents to charge with a bedroom tax – it seems they have found another one. Single mums who need help making an absent father pay for his children – it's your turn to feel like a failure. Again.

But let's say you're a mother whose ex still doesn't cough up and you ask them to make him pay: he'll be charged an extra 20% and you will have 4% of your child's maintenance deducted. The Department for Work and Pensions will be keeping all these fees. The application fee won't apply to domestic violence victims, but collection charges will, if the service has to collect the money from a violent ex. There are so many ways in which this leaves vulnerable families exposed to pressure, or coercion into accepting feeble settlements, it doesn't bear thinking about.

As a single parent, I find it terrifying. My ex and I narrowly avoided all this by sorting out a healthy financial arrangement between ourselves – just as the government would like. But knowing the CSA is there to fall back on has undoubtedly kept me strong during uncertain times.

The thing about friendly arrangements between people who aren't very friendly is that they can disappear overnight. Nobody dreams of going to the CSA – it is already a last resort, and it can be a long struggle to pursue a claim. One friend's ex-partner took advantage of that time delay by dissolving his company and moving his money around so, by the time their case was seen, he looked skint on paper. This man is a successful media figure who appears in the broadsheets and on the BBC.

But the CSA's shortcomings don't mean you should get rid of it altogether. As Fiona Weir, chief executive of single parents charity Gingerbread, said today: "We fear that many parents will be pressured by their ex and by the new charges to stay out of the new system, and instead will enter into a private arrangement that offers no guarantee of regular, reliable income for their children."

A big belch of morality always comes with the Tories' cuts, and this one speaks of adults being reasonable with one another, as if it is the mark of a civilised society that we shouldn't need things like the CSA to exist at all.

Certainly, if you think the mark of civilisation is people being able to grow up and just get along, the CSA won't be something you hold dear. Nor, presumably, will the police be – as you're doubtless able to sort out your own disagreements in other sorts of crimes. A judiciary also won't be of much interest to you, I presume, as your legal battles are always settled out of court, with a slap on the back and a gentlemanly handshake.

In my view, the civilised society is one that formalises the understanding that parents should contribute to their children's upkeep, ideally with their time, love and money – but failing that, just their money. It is good that our society tackles this in a formal way.

So I wonder if our law courts will no longer be available to those wealthy couples who spend months arguing before judges about whether the one with £200m should give their ex more than the £30m they've offered. Are these feuding exes going to be told to get out of our courts and stop wasting our time or risk a fine? Of course not. They're rich.